In a current communications network, there are many complex network devices, such as a router, a network management system, a switch, a firewall, and various types of servers. These devices support various types of network protocols, so as to implement interworking between network elements. Because each device has its own independent control module, network deployment and management are very complex due to such a distributed deployment of control modules. To modify a control parameter or upgrade a control module, a network operator needs to separately operate each device.
To achieve flexible and manageable deployment of network elements, a concept of software-defined networking (SDN for short) is put forward in the industry. By means of SDN, control logic of a network element is decoupled from a forwarding function, and the control logic is deployed in a centralized manner, so that network control and maintenance work can be implemented simply by operating a control plane device. In this way, network management efficiency is improved, and the forwarding-plane device is simpler, which helps achieve high performance and reusability of the forwarding device. Currently, the idea of SDN is widely applied to data center networks and telecommunications networks.
The prior art provides a method for decoupling control from forwarding in SDN, where a network includes a control plane and a forwarding-plane device, and the control plane controls the forwarding-plane device by delivering flow match information and a corresponding context, so as to process a data packet of a user. The flow match information is used to determine a service flow to which the packet belongs, and the context indicates a particular processing function. Each service flow may correspond to or may be associated with multiple contexts, and these contexts are independent from each other, so as to achieve relative independence between various types of processing of the flow-granularity packet, thereby making parallel processing and processing capability expansion easier.
In the prior art, because a forwarding-plane device processes all packets according to contexts, there is a relatively high requirement on the forwarding-plane device, and load on the forwarding-plane device is relatively great, which is bad for improvement of overall network performance.